Orthodontic brackets are used by orthodontists in preventing and treating facial and dental irregularities, such as malocclusions. Patients seeking treatment from orthodontists are concerned with the presence of crooked teeth, or more particularly dental crowding, flaring, irregularity in tooth alignment, unpleasing tooth appearance, “gummy” smile, and difficulty in chewing, among other issues.
Orthodontic treatment can correct the issues listed above as well as treat other cosmetic and oral irregularities and issues. Issues requiring orthodontic treatment may be the result of discrepancies between the supporting bony structures that house the upper and lower dental arches. Orthodontic treatment can address these discrepancies in order to provide a pleasing smile and a proper chewing function while achieving a long-term stability. Trained and experienced orthodontists seek to reach these goals for the dental patient using various techniques and related equipment and products.
One such product used extensively by orthodontists to correct tooth and jaw irregularities and issues is an orthodontic bracket. Orthodontic brackets are secured to patients' teeth and are used by orthodontists to straighten, move or shift the patient's teeth. Orthodontic brackets are designed to achieve at least two basic objectives: to provide for attachment to a tooth, and to hold an orthodontic archwire. The orthodontic bracket works like an intermediate by connecting an orthodontic archwire to a tooth.
The attachment of the bracket to a tooth transmits a force to a tooth when a resilient orthodontic archwire is bent or twisted, and then brought to engage with the bracket. The archwire coupled to orthodontic brackets mounted on a patient's teeth provides for a mechanical force system that functions to sequentially deliver forces to a patient's teeth, thus directing teeth to the proper positions by the work of the orthodontist.
Conventional orthodontic bracket designs permit the engagement of an archwire into an archwire slot by ligation using elastomeric or wire ligatures wrapped around the tie wings of the bracket. Ligatures or some form of fastening means are essential to secure an archwire in the bracket slot to prevent the archwire from being dislodged.
Several problems exist in the use of wire ligation for both the orthodontist and the patient. The application of the ligating wire requires considerable skill on the part of the orthodontist and long chair time for the patient. Moreover, the archwire must be removed from the orthodontic bracket from time to time for bending or replacement during the course of treatment, calling for repetitive ligating operations and increased patient/orthodontist time.
Traditional wire ligation has other disadvantages as well. Ligation with wire creates undesirable nooks and crevices freely exposed to the harsh oral environment that become traps for food particles, and calculus buildup. Also, because tooth movement occurs along the archwire, binding of the archwire with wire ligatures is undesirable because the binding can introduce unwanted resistant forces during orthodontic treatment. The orthodontist must account for these unwanted resistant forces imparted by the ligating wire. Without careful treatment, the intended corrective tooth movement by the orthodontic mechanical forces may be jeopardized.
Elastomeric ligatures also have disadvantages. Elastomeric ligatures have a tendency to discolor and can rapidly lose their elasticity. Accordingly, the efficiency of elastomeric ligatures in securing the archwire to the orthodontic bracket diminishes over time. Elastomeric ligatures can become ineffective or fail, requiring frequent replacement.
One way to address the disadvantages in traditional ligating methods and products is to incorporate a rapid archwire retention and release mechanism so that the need for ligating wires, elastomeric ligatures, and the like may be reduced, if not completely eliminated. Self-ligating bracket systems attempt to address the disadvantages of traditional ligating methods and products wherein the bracket is capable of retaining the archwire without the need for separate ligating wires or elastomeric ligatures. A self-ligating bracket can be positioned in an open position to allow for insertion or release of the archwire into the archwire slot and a closed position to retain the archwire in the archwire slot.
Problems exist in known self-ligating brackets. Due to complexities of manufacturing and assembly processes associated with orthodontic brackets, a self-ligating bracket with a sliding ligating member is challenging to produce in a cost-effective and efficient manner. Many existing self-ligating designs suffer from high scrap rates.
The difficulties associated with manufacturing and assembling known self-ligating brackets may also result in difficulty in use during orthodontic treatment. In designs in which the self-ligating bracket includes a sliding ligating member, the movable ligating member must be retained in a position such that the ligating member covers the archwire slot. Existing self-ligating designs often fail after only a few cycles of moving the ligating member from an open to a closed position. Further, the force required to open and close known ligating members can vary greatly with different issues. In cases where the force required to move the ligating member is too low, the ligating member may not be sufficiently retained in the closed position and thus cannot reliably retain the archwire. In cases where the force required to move the ligating member to the closed position is too high, an orthodontist may not be able to close the ligating member or the effort to close the ligating member translated into discomfort for the patient during treatment.
Therefore, there exists a need for an improved self-ligating bracket that addresses one or more of the disadvantages and problems discussed above. In one embodiment, the present disclosure describes a self-ligating bracket that includes a reliable way of retaining an archwire without the need for separate wire or elastomeric ligatures. The present disclosure also describes a self-ligating bracket that is more easily manufactured and reduces the scrap rate from that of existing designs. Still further, the present disclosure includes a repeatable, durable design for retaining or biasing the ligating member in the open or closed position.
Still another advantage is the ease of use in the clinical environment. This is especially evident in the case of lingual orthodontic brackets. Although the majority of orthodontic brackets are placed on the outer surface of teeth (labial surface), that is the area facing the labial tissue of the patient or the area generally visible to others, some patients opt for a cosmetic approach towards treatment. Lingual brackets allow for orthodontic treatment, not visibly apparent to others, where the bracket is bonded on a lingual surface of the tooth. Lingual brackets are particularly difficult to manipulate by an orthodontist due to limited access within the patient's mouth. The present disclosure describes an easy to use self-ligating bracket that permits easy manipulation of the ligating member by an orthodontist.